Partially hydrolyzed aluminum alkyl compounds known as aluminoxanes (AO) are used for activating transition metals for olefin polymerization activity. One such compound, methylaluminoxane (MAO), is a frequently chosen aluminum co-catalystlactivator in the industry. Considerable effort has been devoted to improving the effectiveness of catalyst systems based on use of aluminoxanes or modified aluminoxanes for polymerization of olefins. Representative patents and publications in the field of aluminoxane usage include the following: U.S. Pat. No. 5,324,800 to Welborn et al.; U.S. Pat. No. 4,752,597 to Turner; U.S. Pat. Nos. 4,960,878 and 5,041,584 to Crapo et al.; WO 96102580 to Dall'occo, et al.; EP 0 277 003 and EP 0 277 004 to Turner; Hlatky, Turner, and Eckman, J. Am. Chem, Soc., 1989, III, 2728-2729; Hlatky and Upton, Macromolecules, 1996, 29, 8019-8020. U.S. Pat. No. 5,153,157 to Hlatky and Turner; U.S. Pat. No. 5,198,401 to Turner, Hlatky, and Eckman; Brintzinger, et al., Angew. Chem. Int. Ed. Engl., 1995, 34, 1143-1170; and the like. Despite technological advances, many aluminoxane-based polymerization catalyst activators still lack the activation efficiencies needed for commercial applicability, require commercially unacceptably high aluminum loading, are expensive (especially MAO), and have other impediments to commercial implementation.
Lewis base stabilized dialkylalaminium cations derived from non-aluminoxane systems and their activation characteristics are described by Klosin et al in WO 2000/011006 and Organometallics, 19 (2000) 4684-4686. Ionic MAO has been isolated from non-ionic regular MAO through the treatment with a bidentate (or chelating) agent, e.g., octamethyltrisiloxane by Sangokoya et al (WO 2003/082879 and WO 2007/005400). Later, through spiking the dimethylaluminum cation THF complex formed through the reaction of trityl tetrakis(pentafluorophenyl)borate with trimethylaluminum (TMA) in tetrahydrofuran (THF) into regular MAO treated with THF, Luo et al identified dimethylaluminum cation THF complex formed in the THF treated MAO (WO 2009/029857 and US 2009/0062492) Furthermore. Luo et al also demonstrated that, through the treatment of a so-called dimethylaluminum cation precursor agent, the number of dimethylaluminum cations in MAO could be significantly increased and therefore the MAO activation efficiency was largely improved (Luo et al in WO 2009/029857 and US 2009/0062492). More recently, through the design of a metallocene with the NMR detectable leaving groups, the dimethylaluminum cation precursor in MAO has been identified as the major active species to activate a metallocene through the extraction of the dimethylaluminum cation precursor from MAO to form the cationic, metallocene leaving group bridging bimetallic complex shown as A in Reaction 1 as an example, which is further converted to a fully alkylated, stable chelating cationic bimetallic complex as B in Reaction 1 (Luo, et al, Advances in Polyolefins 2009, Meeting Abstract, Santa Rosa, Calif., 2009). Such fully alkylated, stable chelating cationic bimetallic complexes have long been recognized as the major metallocene derived species formed when a metallocene is activated with MAO, e.g., cationic bimetallic zirconocene species (Babushkin & Brinztinger, J. Am. Chem. Soc., 2002, 124, 12869) and the cationic bimetallic titanocene species (Bryliakov, Talsi, and Bochmann, Organometallics, 2004, 23,149).
Dimethylaluminum Cation Preursor

Thus, a need remains for AO-type compositions that exhibit higher efficiencies for activating transition metals for olefin polymerization over conventional AO, in particular, compositions with more active species comprising the dialkylaluminum cation or its precursor in aluminoxane type activators through more economically sound methods to significantly reduce the aluminoxane ratio in a practical catalytic system in order to reduce the cost of making the metallocene/single-site catalysts.